1. Field of the Invention
The present invention relates to a motor speed controller for controlling the rotational speed of a motor by feedback control.
2. Description of the Related Art
The speed of a motor can be controlled by obtaining from a motor module a pulse signal PT in which the period varies in accordance with the rotational speed ω of the motor. A motor speed controller measures the period τP of the pulses appearing in a pulse signal, detects the rotational speed ω of the motor from that period, and performs feedback control so that the rotational speed ω is brought to a target value ωT.
For example, if two kinds of pulse signals PI generated in synchronization with rotational positions that are mutually different by 90° are obtained from the motor, then the direction of rotation of the motor can be identified in the motor speed controller.
[Patent Document]
    Japanese Laid-open Patent Publication No. 8-126374